Workholder for bar-grinding machines



April 8, 1930. F. K. BENEDICT WORKHOLDER FOR BAR GRINDING MACHINES 3Sheets-Sheet 1 Filed Dec. 27, 1927 IN VEN T 0 1? BYF/PEDE/P/C A.BENEDICT April 8, 1930. F. K. BENEDHCT 1,753,590

WORKHOLDER FOR BAR GRINDING MACHINES Filed Dec 27, 1927 s sheets-sheet 216 \l GD 6 [7 -12 D Q Q 0 9 r O we 7 10 v R INVENTOR FREUL'R/C K.5'/v0/cr A TTORNE Y April 8, 1930. F. K.

' WORKHOLDER FOR BAR GRINDING MACHINES BENEDICT s Sheets-Sheet 5 FiledDec. 2'7, 1927 INVENTOR F/Q fDE/P/C A? BDVEU/CT TZ'ORNEY Patented Apr.8, 1930 FREDERIG K. BENEDICT, OF BIG RAPIDS, MICHIGAN, ASSIGNOR TOCOVEL-HANCHETT (30., OF BIG RAPIDS, MICHIGAN, A CORPORATION MICHIGANWORKHOLDER FOR BAR-GRINDING- MACHINES Application filed December 27,1927. Serial No. 242,795.

This invention is a work-holder for a grinding machine used for grindingthe flat working faces of bars, and for face-grinding other heavy workof like character.

My invention comprises a work-holder that is rotatable about its centralvertical axis, and is provided with work-clamping and releasing means onboth sides. Novel centering devices and locking mechanism for accuratelypositioning and locking the work-holder with respect to the grindingelement are also provided on the rotatable work-holder. The grindingelement is a motor-driven grinding wheel mounted on a carriage thattravels back and forth along the face of "the work.

An object of my invention as claimed is to provide a rotatablework-holder that presents a piece of work to the grinding wheel andwhile it is being faced off a second piece of work is being mounted andaccurately positioned and clamped on the back of the workholder. Whenthe first piece is finished the holder is rotated to accurately presentthe second piece of work to the wheel. r

The invention includes novel means for easily clamping the work on thework-holder, for adjusting it inwardly toward and from the working planeof the grinding wheel, for tilting the upright face to be'worked towardor away from the working plane of the wheel, and gauging means forsetting the face of the bearing patches on the bar in a true verticalplane in order that the finished Working face shall be parallel with theface of the patch. A locomotive guide bar is a heavy piece of work quitewide and several'feet long, and its working face, on which the enginecross head is to slide, must be ground to a true plane and it must alsobe parallel with thefaced pads or 49 bearing surfaces that are providedon the back face of the bar'near its ends. Ease and accuracy in settingand adjusting these heavy pieces of work on the vertical work-holderwhile another piece is being ground are essen- 5 tial considerations,and the novel means for within a housing 2 is attaining that facility ofhandling is part-0f my claimed invention.

Another advantage is that the grinding wheel and its supporting carriagecan be run out of the way by continuing along the extended track onwhich it travels, to permit the work-holder to be, rotated and therebypresent a new piece of Work to the grinding wheel, after which the wheelcan be returned without having disturbed its accuracy.

lVith the foregoing and certain other objects in View which will appearlater in the specifications, my invention comprises the devices hereindescribed and claimed and the equivalents thereof.

In the drawings Fig. 1 is a front perspective view of the machine whilegrinding.

Fig. 2 isan end view of the work-holder in perspective.

a Fig. 3 is a perspective view showing the work-holder while beingrotated, the grinding wheel mechanism at the end of its travel to clearthe work-holder.

Fig. 4 is a rear view of an end of the workholder, partly broken away,showing the locking device.

' Fig. 5 is an end view, partly broken away.

Fig. 6 is a detail View of the plunger that locks the turn table.

As clearly shown in the drawings a cupshaped grinding wheel -1 suitablymounted driven by a motor 3 through a silent chain 4.

The housing is traversed along ways 5 in the manner common in this classof machines. Alongside the ways 5 is a bed or platen 6, upon which thework-holder which forms the subject of my invention is mounted.

Considered in its broader aspect the workholder comprises a turn-table 7revolvablein a horizontal plane around a vertical axis. Near the ends ofthe turn-table are upright work-supporting cradles 8 adapted to hold twopieces of work, one on the front of the turn-table and one on the back.

\Vhile one of the pieces A is being faced 01f by the grinding wheel theother piece B is being mounted on the turn table, the workman standingat the back, or right-hand side cf the machine, as represented in Fig.1, while setting the work. The piece B is placed in the cradles 8, theends of its lower edge resting on blocks 9 which are equipped with meansoperated by adjusting screws 10 whereby the face of piece B can beslightly tilted away from vertical, as lines. Such a tilting movement issome times necessary in order to set the work so that the back face ofthe bearing pad 11 on the 3nd of the work will lie in a plane parallelwith the working plane of the grinding wheel. Parallelism of the wheeland. the pad insures that the wheel will dress the outer face of theguide to a plane that is exactlyparallel with Lhe bearing faces of itsend pads 11. A gauge plate having a straight-edge 12 is slidable towardand from the face'of the patch 11, to enable the operator to accuratelygauge the setting of the work. The gauge plate may be clamped in placeby a set screw 13.

The tilting mechanism actuated by screw 10 is shown in side view in Fig.5, where 1a is a work-supporting bar concealed within the block 9 andpivotally mounted, as at 15, so that downward thrust'of adjusting screw10 raises the outer end of bar 1a and tilts it slightly, correspondinglytilting the guide bar 7B. The bar is then clamped down by screws 16 andis backed up by adjusting screws 17 which are carried by the cradles 8.To ascertain whether the piece B when set up on the back of theturn-table in the way above described has been accurately aligned withthe working face of the grinding wheel 2, face gauges 18, 18 are mountedon the back edge of platen'6. They are hinged at their bottoms tobrackets 19 and can be folded down out of the way when the turn-tablerevolves, as shown in Fig. 3. By raising these two gauges and sweepingthem in the arc of a circle over the front face of work B thecorrectness of the setting can be determined by inspection.

When the turn-table is in the position shown in Fig. 1 its ends rest onsupporting blocks 20 and are clamped down to those blocks by means of ascrew and lug 21.

To insure accuracy of longitudinal alignment of the turn-table with theworking plane of the grinding wheel I provide a locking plunger 22, Fig.6, the end of which normally engages an accurately formed recess 23 inthe under side of the turn-table. A spring 24 concealed in a cavity ofthe plunger serves to keep the plunger normally raised, and a pivotedhandle 25 when lifted retracts the plunger and releases the turn-tableso it can be revolved.

After the working face of piece A has been finished by the grindingwheel 1 the wheel indicated by dotted and its associated drivingmechanism on housing 2 is run past the turn-table far enough to allowthe table to swing, as shown in Fig. 3, to present piece B to thegrinding wheel for the next operation.

The turn-table is preferably mounted upon anti-friction bearings 26carried by the stationary platen 6, as shown in Figs. 4: and 5.

I In operating the machine'the piece B is first stood on edge on thetiltable blocks 9, 9 and its back pad faces are set vertical by gauges12 and adjusting screws 10, after which the work is clamped down byscrews 16 and supported at its back by adjusting screws 17 The facegauges 18 are then used to check up the accuracy of the setting as theyare properly located to represent the true position of the working faceof grinding wheel 1 with respect to piece B for reversing theturn-table.

By the means above described I have produced a machine for grinding thefaces of locomotive cross heads or guide bars and for other grinding orpolishing work that requires the grinding of a true fiat surface ofconsiderable length and width in a plane that is parallel with andequidistant from the faces of the bearing pad surfaces that are on theback of the work. 7

Moreover, I have provided novel means for mounting the work, foraccurately placing it prior to grinding so as to present it correctly tothe grinding wheel.

I have also provided'a work-holding platen carrying a pair of cradles ateach side whereby a piece of work can be accurately positioned on onepair of cradles While another piece, previously mounted in the oppositepair of cradles, is being ground.

In practice the machine can be kept in practically continuous operation,since the operator can mount and accurately position one piece of workwhile the grinding wheel is automatically facing a previous 1 piece ofwork.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

1. In a machine for face-grinding locomotive guides and similar work, aturn table having upright work-supporting cradles at its ends remotefrom its axis, each cradle pro- .vided with two oppositely directedpivotally mounted work-supporting bars, means for adj ustably tiltingeach bar independently, means for clamping an end of a piece of workdown upon a tiltable bar, an adjustable gauge plate co-operativelyassociated with the worksupporting bar, and a pair of face gauges hingedat their bottoms to fixed supports near the ends of the work and adaptedto be swept in the arc of a circle 'over the front face of the work,forthe purposes set forth.

2. In a machine for face-grinding locomo-' tive guides and similar work,a turn table having upright work-supporting cradles at its ends remotefrom its axis, each cradle provided with two oppositely directedpivotally mounted Work-supporting bars, means for adj ustably tiltingeach bar independently, means for clamping an end of a piece of Workdown upon a tiltable bar, and a pair of face gauges hinged at theirbottoms to fixed supports near the ends of the work and adapted to beswept in the arc of circles in a plane 0 corresponding to the front faceof the Work,

for the purposes set forth.

In testimony whereof, I affix my signature.

FREDERIG K. BENEDICT.

